Acute body sodium depletion induces skin sodium mobilization in female Wistar rats

Oestradiol, which is an important hormone for water and electrolyte balance, also has a role in the inhibition of induced Na+ appetite. Sodium can be stored in the skin in osmotically active or inactive forms, and this skin Na+ reservoir may be involved in the control of body Na+ levels during physiopathological challenges. In this study, we investigated whether the effect of sodium depletion by frusemide can mobilize Na+ from the skin reservoir and whetheroestradiol replacement changes or mobilizes theNa+ reserves in the skin. Ovariectomized Wistar rats were treated with vehicle or oestradiol for 7 days to evaluate the effects of oestrogen on the hydroelectrolyte balance, intake responses and skin Na+ and water content in basal conditions. Furthermore, the effects of oestrogen were evaluated after 24 h frusemide-inducedwhole-body Na+ depletion. Oestradiol-replaced rats exhibited reduced water intake without any significant changes in salt intake,Na+ excretion orwater andNa+ skin content in basal conditions.After sodium depletion, both vehicle- and oestradiol-treated rats exhibited an increase in the osmotically active skin Na+, which was associated with a decrease of the inactive skin Na+ reservoir. Oestrogen decreased the hypertonic saline intake induced by Na+ depletion, but it was not associated with any significant changes in the skin Na+ reservoir. Thus, sodium depletionis able to change the inactive?active skin Na+ reservoir balance. However, the oestrogenic modulation of sodium appetite after Na+ depletion is probably not related to the action of this hormone in the skin Na+ reservoir balance.Fil: Lopes-Menezes, V. C.. Universidade Federal do Rio de Janeiro; BrasilFil: Dos-Santos, R. C.. Universidade Federal do Rio de Janeiro; BrasilFil: Felintro, V.. Universidade Federal do Rio de Janeiro; BrasilFil: Monteiro, L. R. N.. Universidade Federal do Rio de Janeiro; BrasilFil: Paes-Leme, B.. Universidade Federal do Rio de Janeiro; BrasilFil: Lustrino, D.. Universidade Federal do Rio de Janeiro; BrasilFil: Casartelli, Marina Paola. Universidad Nacional de Mar del Plata. Facultad de Humanidades. Centro de Estudios Sociales y Politicos.; ArgentinaFil: Vivas, Laura Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; ArgentinaFil: Mecawi, Andre Souza. Universidade Federal do Rio de Janeiro; BrasilFil: Reis, L. C.. Universidade Federal do Rio de Janeiro; Brasi